A passenger riding an elevator is subjected to a change in atmospheric pressure. Atmospheric air pressure can be described as the pressure at any given point in the earth's atmosphere. Atmospheric air pressure increases as an elevator travels downward, and decreases as an elevator travels upward. If these pressure changes occur too rapidly, they may cause passenger discomfort, specifically to a passenger's ears.
The ear can be divided into three sections: (1) the outer ear, (2) the middle ear, and (3) the inner ear. The middle ear is an air-filled chamber that is connected to the nose and throat through a channel called the eustachian tube. The middle ear is surrounded at respective sides by the outer ear and the inner ear. Air moves through the eustachian tube into the middle ear to equalize the pressure with the pressure of the outer ear. The middle ear contains the tympanic member, otherwise known as the ear drum. Hence, the pressure in the middle ear is often referred to as the typmanic pressure.
When an elevator travels upwards, the air pressure of the outer ear decreases with the atmospheric pressure. Compared to the outer ear, the pressure in the middle ear generally does not adjust as quickly to pressure changes. The automatic adjustment for pressure differences in the normal human ear will be referred to as “natural relief.” The outer ear therefore has lower air pressure compared to the middle ear due to the middle ear's slower adjustment to pressure changes. The air pressure in the middle air remains higher until equalized. The tympanic membrane of the ear, otherwise known as the eardrum, may bulge towards the outer ear in reaction to having a higher pressure in the middle ear. If this bulge becomes too great, the person may experience discomfort, or injury to the eardrum including small hemorrhages in the ear drum, small blisters, or other injuries. In extreme cases, the eardrum may rupture, which may lead to permanent damage.
Alternatively, where a passenger descends a building, the atmospheric pressure increases in the outer ear. This pressure increase in the outer ear results in the pressure in the middle ear being lower compared to the outer ear. This pressure difference between the outer ear and the middle ear can cause the tympanic membrane of the ear to bulge inward toward the middle ear. If this bulge becomes too great, the person may experience discomfort, small hemorrhages in the ear drum, small blisters, or other injuries. In extreme cases, the eardrum may rupture, which may lead to permanent damage.
Yet further, if the person has a cold or other condition that causes partial or complete blockage of the Eustachian tube, natural relief may not be able to equalize the increased pressure difference, such that discomfort may persist for an extended period of time. Also, the sudden opening of the Eustachian tube may force a rapid pressure change in the middle ear. This sudden pressure change in the middle ear can be further transmitted to the inner ear and possibly damage the delicate mechanisms of the middle ear (i.e. the ear drum) and the inner ear.
In view of the previous discussion, it is desirable to limit the rate of the pressure changes to which passengers are exposed while riding an elevator. A system and apparatus is disclosed that will allow an elevator system to run efficiently while limiting the rate of air pressure changes to which passengers are exposed.